docs(goal_planner): update README

mkdocs_macros.py

@@ -1,4 +1,5 @@
 import json
+import urllib
 
 from tabulate import tabulate
 
@@ -70,3 +71,8 @@ def json_to_markdown(json_schema_file_path):
         with open(json_schema_file_path) as f:
             data = json.load(f)
             return format_json(data)
+
+    @env.macro
+    def drawio(image_path):
+        image_url = urllib.parse.quote(f"{env.conf['site_url']}{image_path}", "")
+        return f"https://app.diagrams.net/?lightbox=1#U{image_url}"